Abstract: A method for managing a cache memory, including executing first and second processes, when the second process modifies the state of the cache memory, updating the value of an indicator associated with this second process, and comparing the value of this indicator to a predefined threshold and, when this predefined threshold is exceeded, detecting an abnormal use of the cache memory by the second process, in response to this detection, modifying pre-recorded relationships in order to associate with the identifier of the second process a value of a parameter q different from the value of the parameter q associated with the first process so that, after this modification, when the received address of a word to be read is the same for the first and second processes, then the set addresses used to read this word from the cache memory are different.

Abstract: Method for managing a cache memory comprising: the transformation of a received set address in order to find a word in the cache memory, into a transformed set address by means of a bijective transformation function, the selection of one or more line tags stored in the cache memory at the transformed set address. in which: the transformation function is parameterized by a parameter q such that the transformed set address obtained depends both on the received set address and on the value of this parameter q, and for all the non-zero values of the parameter q, the transformation function permutes at least 50% of the set addresses, and during the same execution of the process, a new value of the parameter q is repeatedly generated for modifying the transformation function.

Abstract: In this method, a securing hardware module of a microprocessor: 1) verifies (176) the integrity and the authenticity of a cryptogram contained in a code line loaded with the aid of a message authentication code contained in this same line and triggers (172) the signalling of an execution fault if the integrity or the authenticity of the cryptogram is not confirmed, and then 2) decrypts (178) the cryptogram to obtain a decrypted instruction or a decrypted datum if the integrity and the authenticity of the cryptogram are confirmed, and then: in the case of a decrypted instruction, the decrypted instruction is recorded (180) in a queue of instructions to be executed successively one after another by an arithmetic and logic unit of the microprocessor, and in the case of a decrypted datum, the decrypted datum is recorded in an internal register of the microprocessor while waiting to be processed by the arithmetic and logic unit.

Abstract: A method for executing a polymorphic machine code, wherein: for each branching address at which a base block of a flow of generated instructions starts, the microprocessor automatically adds, in the generated flow of instructions, a renewal instruction suitable, when it is executed, for triggering the renewal of an initialization vector of a module for decryption by flow with a specific value associated with this branching address, then a flow encryption module encrypts the flow of instructions as it is generated and, during this encryption, each base block is encrypted using a specific value associated with the branching address at which it starts. Only the instruction flow encrypted in this way is recorded in the main memory. During execution of the encrypted instruction flow, the added renewal instructions are executed as they are encountered.

Abstract: The invention relates to an RFID tag adapted to access a service of interest from an access terminal, said RFID tag (1) comprising an integrated circuit (3) configured to: enable a cryptographic authentication of the RFID tag (1) by said access terminal (7) using a current cryptography key shared by the RFID tag (1) and the access terminal (7), said authentication allowing access to said service of interest, and enable the RFID tag (1) to recover a new current cryptography key updated by an NFC smartphone after said NFC smartphone has authenticated the RFID tag (1), using an initial cryptography key previously shared between the RFID tag (1) and said smartphone.

Abstract: A method of managing implicit certificates of an elliptical curve encryption (ECQV). The implicit certificates are stored in different nodes of the network as a function of a distributed hash table (DHT) and not with a single certification authority. The implicit certificate of the public key associated with a node is obtained by chaining elementary certification operations with a sequence of indexing nodes of the network. Chaining of elementary certification operations can reinforce authentication of network nodes.

Abstract: A method of executing a program operating on data encrypted by a homomorphic encryption. Execution of a program instruction includes the homomorphic evaluation of an associated function in the ciphertext space, homomorphic masking of the result of the evaluation with a previously encrypted random sequence, decryption of the evaluation result thus masked followed by a new encryption and then homomorphic unmasking in the ciphertext space. The result of execution of the instruction does not appear in plain text at any time during execution of the instruction.

Abstract: A method of encrypting a program instructions stream and a method of executing an instructions stream thus encrypted. Instructions are translated into binary code before being encrypted by a stream cipher method. When the program contains a conditional or unconditional branch instruction, an instruction is inserted in the program to initialize the pseudo-random sequence generator using an initialization vector, the initialization vector being used to generate the pseudo-random sequence for encryption and decryption of instructions at the branch address. Instructions can be decrypted and executed on-the-fly without needing to know their physical addresses, even in the presence of a branch.

Abstract: The invention relates to an RFID tag adapted to access a service of interest from an access terminal, said RFID tag (1) comprising an integrated circuit (3) configured to: enable a cryptographic authentication of the RFID tag (1) by said access terminal (7) using a current cryptography key shared by the RFID tag (1) and the access terminal (7), said authentication allowing access to said service of interest, and enable the RFID tag (1) to recover a new current cryptography key updated by an NFC smartphone after said NFC smartphone has authenticated the RFID tag (1), using an initial cryptography key previously shared between the RFID tag (1) and said smartphone.

Abstract: A method including the loading into registers of a microprocessor of a code line recorded at an address @j, and then calculating, with a securing hardware module, an initialization vector with the aid of a relation ivj=Fiv(@j), where @j is the address from which the code line was loaded, and then decrypting, with the securing hardware module, the code line loaded with the aid of the initialization vector calculated to obtain: a datum Dj of its cryptogram, and a first error-detecting code, and then verifying, with the securing hardware module and with the aid of the first error-detecting code obtained, whether there exists an error in the datum Dj or its cryptogram and, if such an error exists, triggering the signalling of an execution fault and, if such an error does not exist, inhibiting this signalling of an execution fault.

Abstract: In this method, a securing hardware module of a microprocessor: 1) verifies (176) the integrity and the authenticity of a cryptogram contained in a code line loaded with the aid of a message authentication code contained in this same line and triggers (172) the signalling of an execution fault if the integrity or the authenticity of the cryptogram is not confirmed, and then 2) decrypts (178) the cryptogram to obtain a decrypted instruction or a decrypted datum if the integrity and the authenticity of the cryptogram are confirmed, and then: in the case of a decrypted instruction, the decrypted instruction is recorded (180) in a queue of instructions to be executed successively one after another by an arithmetic and logic unit of the microprocessor, and in the case of a decrypted datum, the decrypted datum is recorded in an internal register of the microprocessor while waiting to be processed by the arithmetic and logic unit.

Abstract: A method for an industrial printer to secure at least one consumable or detachable element, the printer comprising a 1st microcontroller that will make a data transfer with a 2nd microcontroller of the printer or the consumable or detachable element, this method including at least: an authentication of the 2nd microcontroller by the 1st microcontroller, one of the microcontrollers sends at least one secret key Sk for data transfers between the two microcontrollers, to the other microcontroller, data exchange between the two microcontrollers by symmetric encryption using the first data transfer secret key Sk1.

Abstract: A method of managing implicit certificates of an elliptical curve encryption (ECQV). The implicit certificates are stored in different nodes of the network as a function of a distributed hash table (DHT) and not with a single certification authority. The implicit certificate of the public key associated with a node is obtained by chaining elementary certification operations with a sequence of indexing nodes of the network. Chaining of elementary certification operations can reinforce authentication of network nodes.

Abstract: A method of executing a program operating on data encrypted by a homomorphic encryption. Execution of a program instruction includes the homomorphic evaluation of an associated function in the ciphertext space, homomorphic masking of the result of the evaluation with a previously encrypted random sequence decryption of the evaluation result thus masked followed by a new encryption and then homomorphic unmasking in the ciphertext space. The result of execution of the instruction does not appear in plain text at any time during execution of the instruction.

Abstract: A method of encrypting a program instructions stream and a method of executing an instructions stream thus encrypted. Instructions are translated into binary code before being encrypted by a stream cipher method. When the program contains a conditional or unconditional branch instruction, an instruction is inserted in the program to initialise the pseudo-random sequence generator using an initialisation vector, the initialisation vector being used to generate the pseudo-random sequence for encryption and decryption of instructions at the branch address. Instructions can be decrypted and executed on-the-fly without needing to know their physical addresses, even in the presence of a branch.

Abstract: A method for securing a wireless communication between a transmitter and a receiver includes: reception of a signal by the receiver; extraction by the receiver of at least one noise parameter of this signal received; comparison of the extracted noise parameter with at least one corresponding reference noise parameter stored in a memory in the receiver; decision on the presence or absence of a relay device between the transmitter and the receiver according to the result of this comparison; a preliminary calibration of the receiver, wherein: the receiver receives a signal resulting from a direct communication with the transmitter without intervention of a relay device, the receiver extracts at least one noise parameter from the signal received, and the receiver stores this noise parameter in the memory as a reference noise parameter characteristic of a direct communication without a relay device between the transmitter and the receiver.

Abstract: A method for detecting a contactless receiver in a field of an antenna of a contactless reader includes during a first ramp interval, exciting the antenna by applying a potential difference comprising a ramp between first and second values of the potential difference, and during a first plateau interval following the first ramp interval, maintaining the potential difference at the second value of the potential difference, while maintaining the potential difference at the plateau, measuring a response of the antenna, comparing the measured response and a reference response, and determining presence of a contactless receiver in the field of the antenna based at least in part on a result of the comparison.

Abstract: A method of protection of a near-field contactless communication system against malicious attacks. The method includes exchange of information between a reader and a contactless card of duration T, measured with respect to a starting instant t0 seen from the reader, decoding of this information by the card, sending by the card a return signal temporally set with respect to an instant t?0+T, where t?0 is the starting instant as seen by the card taking into account delays in propagation or processing of signals received from the reader, detection of the return signal by the reader, determination of the temporal setting of the return signal with respect to the starting instant t0, and interruption of communication by the reader if the temporal setting of the return signal detected is not equal to the instant t0+T with a predetermined margin of error. The return signal is a pseudo-random sequence.

Abstract: A method for securing a wireless communication between a transmitter and a receiver includes: reception of a signal by the receiver; extraction by the receiver of at least one noise parameter of this signal received; comparison of the extracted noise parameter with at least one corresponding reference noise parameter stored in a memory in the receiver; decision on the presence or absence of a relay device between the transmitter and the receiver according to the result of this comparison; a preliminary calibration of the receiver, wherein: the receiver receives a signal resulting from a direct communication with the transmitter without intervention of a relay device, the receiver extracts at least one noise parameter from the signal received, and the receiver stores this noise parameter in the memory as a reference noise parameter characteristic of a direct communication without a relay device between the transmitter and the receiver.

Abstract: A method for detecting a contactless receiver in a field of an antenna of a contactless reader includes during a first ramp interval, exciting the antenna by applying a potential difference comprising a ramp between first and second values of the potential difference, and during a first plateau interval following the first ramp interval, maintaining the potential difference at the second value of the potential difference, while maintaining the potential difference at the plateau, measuring a response of the antenna, comparing the measured response and a reference response, and determining presence of a contactless receiver in the field of the antenna based at least in part on a result of the comparison.